Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux...
[linux-2.6] / drivers / gpio / pca953x.c
1 /*
2  *  pca953x.c - 4/8/16 bit I/O ports
3  *
4  *  Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
5  *  Copyright (C) 2007 Marvell International Ltd.
6  *
7  *  Derived from drivers/i2c/chips/pca9539.c
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License as published by
11  *  the Free Software Foundation; version 2 of the License.
12  */
13
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/i2c.h>
17 #include <linux/i2c/pca953x.h>
18
19 #include <asm/gpio.h>
20
21 #define PCA953X_INPUT          0
22 #define PCA953X_OUTPUT         1
23 #define PCA953X_INVERT         2
24 #define PCA953X_DIRECTION      3
25
26 /* This is temporary - in 2.6.26 i2c_driver_data should replace it. */
27 struct pca953x_desc {
28         char            name[I2C_NAME_SIZE];
29         unsigned long   driver_data;
30 };
31
32 static const struct pca953x_desc pca953x_descs[] = {
33         { "pca9534", 8, },
34         { "pca9535", 16, },
35         { "pca9536", 4, },
36         { "pca9537", 4, },
37         { "pca9538", 8, },
38         { "pca9539", 16, },
39         /* REVISIT several pca955x parts should work here too */
40 };
41
42 struct pca953x_chip {
43         unsigned gpio_start;
44         uint16_t reg_output;
45         uint16_t reg_direction;
46
47         struct i2c_client *client;
48         struct gpio_chip gpio_chip;
49 };
50
51 /* NOTE:  we can't currently rely on fault codes to come from SMBus
52  * calls, so we map all errors to EIO here and return zero otherwise.
53  */
54 static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val)
55 {
56         int ret;
57
58         if (chip->gpio_chip.ngpio <= 8)
59                 ret = i2c_smbus_write_byte_data(chip->client, reg, val);
60         else
61                 ret = i2c_smbus_write_word_data(chip->client, reg << 1, val);
62
63         if (ret < 0) {
64                 dev_err(&chip->client->dev, "failed writing register\n");
65                 return -EIO;
66         }
67
68         return 0;
69 }
70
71 static int pca953x_read_reg(struct pca953x_chip *chip, int reg, uint16_t *val)
72 {
73         int ret;
74
75         if (chip->gpio_chip.ngpio <= 8)
76                 ret = i2c_smbus_read_byte_data(chip->client, reg);
77         else
78                 ret = i2c_smbus_read_word_data(chip->client, reg << 1);
79
80         if (ret < 0) {
81                 dev_err(&chip->client->dev, "failed reading register\n");
82                 return -EIO;
83         }
84
85         *val = (uint16_t)ret;
86         return 0;
87 }
88
89 static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
90 {
91         struct pca953x_chip *chip;
92         uint16_t reg_val;
93         int ret;
94
95         chip = container_of(gc, struct pca953x_chip, gpio_chip);
96
97         reg_val = chip->reg_direction | (1u << off);
98         ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
99         if (ret)
100                 return ret;
101
102         chip->reg_direction = reg_val;
103         return 0;
104 }
105
106 static int pca953x_gpio_direction_output(struct gpio_chip *gc,
107                 unsigned off, int val)
108 {
109         struct pca953x_chip *chip;
110         uint16_t reg_val;
111         int ret;
112
113         chip = container_of(gc, struct pca953x_chip, gpio_chip);
114
115         /* set output level */
116         if (val)
117                 reg_val = chip->reg_output | (1u << off);
118         else
119                 reg_val = chip->reg_output & ~(1u << off);
120
121         ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
122         if (ret)
123                 return ret;
124
125         chip->reg_output = reg_val;
126
127         /* then direction */
128         reg_val = chip->reg_direction & ~(1u << off);
129         ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
130         if (ret)
131                 return ret;
132
133         chip->reg_direction = reg_val;
134         return 0;
135 }
136
137 static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
138 {
139         struct pca953x_chip *chip;
140         uint16_t reg_val;
141         int ret;
142
143         chip = container_of(gc, struct pca953x_chip, gpio_chip);
144
145         ret = pca953x_read_reg(chip, PCA953X_INPUT, &reg_val);
146         if (ret < 0) {
147                 /* NOTE:  diagnostic already emitted; that's all we should
148                  * do unless gpio_*_value_cansleep() calls become different
149                  * from their nonsleeping siblings (and report faults).
150                  */
151                 return 0;
152         }
153
154         return (reg_val & (1u << off)) ? 1 : 0;
155 }
156
157 static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
158 {
159         struct pca953x_chip *chip;
160         uint16_t reg_val;
161         int ret;
162
163         chip = container_of(gc, struct pca953x_chip, gpio_chip);
164
165         if (val)
166                 reg_val = chip->reg_output | (1u << off);
167         else
168                 reg_val = chip->reg_output & ~(1u << off);
169
170         ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
171         if (ret)
172                 return;
173
174         chip->reg_output = reg_val;
175 }
176
177 static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
178 {
179         struct gpio_chip *gc;
180
181         gc = &chip->gpio_chip;
182
183         gc->direction_input  = pca953x_gpio_direction_input;
184         gc->direction_output = pca953x_gpio_direction_output;
185         gc->get = pca953x_gpio_get_value;
186         gc->set = pca953x_gpio_set_value;
187         gc->can_sleep = 1;
188
189         gc->base = chip->gpio_start;
190         gc->ngpio = gpios;
191         gc->label = chip->client->name;
192 }
193
194 static int __devinit pca953x_probe(struct i2c_client *client)
195 {
196         struct pca953x_platform_data *pdata;
197         struct pca953x_chip *chip;
198         int ret, i;
199         const struct pca953x_desc *id = NULL;
200
201         pdata = client->dev.platform_data;
202         if (pdata == NULL)
203                 return -ENODEV;
204
205         /* this loop vanishes when we get i2c_device_id */
206         for (i = 0; i < ARRAY_SIZE(pca953x_descs); i++)
207                 if (!strcmp(pca953x_descs[i].name, client->name)) {
208                         id = pca953x_descs + i;
209                         break;
210                 }
211         if (!id)
212                 return -ENODEV;
213
214         chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
215         if (chip == NULL)
216                 return -ENOMEM;
217
218         chip->client = client;
219
220         chip->gpio_start = pdata->gpio_base;
221
222         /* initialize cached registers from their original values.
223          * we can't share this chip with another i2c master.
224          */
225         pca953x_setup_gpio(chip, id->driver_data);
226
227         ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output);
228         if (ret)
229                 goto out_failed;
230
231         ret = pca953x_read_reg(chip, PCA953X_DIRECTION, &chip->reg_direction);
232         if (ret)
233                 goto out_failed;
234
235         /* set platform specific polarity inversion */
236         ret = pca953x_write_reg(chip, PCA953X_INVERT, pdata->invert);
237         if (ret)
238                 goto out_failed;
239
240
241         ret = gpiochip_add(&chip->gpio_chip);
242         if (ret)
243                 goto out_failed;
244
245         if (pdata->setup) {
246                 ret = pdata->setup(client, chip->gpio_chip.base,
247                                 chip->gpio_chip.ngpio, pdata->context);
248                 if (ret < 0)
249                         dev_warn(&client->dev, "setup failed, %d\n", ret);
250         }
251
252         i2c_set_clientdata(client, chip);
253         return 0;
254
255 out_failed:
256         kfree(chip);
257         return ret;
258 }
259
260 static int pca953x_remove(struct i2c_client *client)
261 {
262         struct pca953x_platform_data *pdata = client->dev.platform_data;
263         struct pca953x_chip *chip = i2c_get_clientdata(client);
264         int ret = 0;
265
266         if (pdata->teardown) {
267                 ret = pdata->teardown(client, chip->gpio_chip.base,
268                                 chip->gpio_chip.ngpio, pdata->context);
269                 if (ret < 0) {
270                         dev_err(&client->dev, "%s failed, %d\n",
271                                         "teardown", ret);
272                         return ret;
273                 }
274         }
275
276         ret = gpiochip_remove(&chip->gpio_chip);
277         if (ret) {
278                 dev_err(&client->dev, "%s failed, %d\n",
279                                 "gpiochip_remove()", ret);
280                 return ret;
281         }
282
283         kfree(chip);
284         return 0;
285 }
286
287 static struct i2c_driver pca953x_driver = {
288         .driver = {
289                 .name   = "pca953x",
290         },
291         .probe          = pca953x_probe,
292         .remove         = pca953x_remove,
293 };
294
295 static int __init pca953x_init(void)
296 {
297         return i2c_add_driver(&pca953x_driver);
298 }
299 module_init(pca953x_init);
300
301 static void __exit pca953x_exit(void)
302 {
303         i2c_del_driver(&pca953x_driver);
304 }
305 module_exit(pca953x_exit);
306
307 MODULE_AUTHOR("eric miao <eric.miao@marvell.com>");
308 MODULE_DESCRIPTION("GPIO expander driver for PCA953x");
309 MODULE_LICENSE("GPL");